The present invention relates to apparatus for wrapping tobacco fillers or bunches to form cigars, cigarillos or analogous smokers' products (hereinafter called cigars). More particularly, the invention relates to improvements in apparatus of the type wherein successive discrete tobacco fillers (hereinafter called bunches) are wrapped into an adhesive-coated web in a manner as disclosed, for example, in the commonly owned U.S. Pat. No. 3,461,881 granted Aug. 19, 1969, to form a series of interconnected cigars which are thereupon separated from each other. Still more particularly, the invention relates to improvements in mechanisms or units which are used in such apparatus to sever or subdivide a continuous wrapper or tube of helically convoluted adhesive-coated strip or web stock to produce discrete cigars.
U.S. Pat. No. 3,461,881 discloses an apparatus wherein a conveyor moves a single file of bunches lengthwise and causes the bunches to rotate about their axes. A web of adhesive-coated wrapping material is fed at an oblique angle so that it is convoluted around the bunches in the form of a helix and forms a continuous tube which is thereupon severed by a cutoff so that the cigars are separated from each other and can be moved lengthwise into a magazine, tray or to another destination. The cutoff comprises a sleeve which moves lengthwise in and counter to the direction of lengthwise movement of the tube and an orbiting knife which also moves in and counter to the direction of lengthwise movement of bunches and severs the tube in the sleeve while moving in the direction of and at the exact speed of movement of the tube. A drawback of such cutoffs is that the mass of their parts is considerable so that they cannot be reciprocated at a speed which is needed in a high-speed apparatus. Thus, such types of severing means limit the output of the cigar making apparatus. Moreover, a cutoff with a reciprocating knife and a reciprocating sleeve is rather complex, expensive and prone to malfunction.
It was further proposed to sever the continuous rotating tube which surrounds a single file of cigar bunches by a knife which does not rotate but merely moves lengthwise with the tube during penetration into the convoluted web. This reduces the mass of moving parts. However, such means for severing the tube also failed to find widespread acceptance because the severing action is performed by a relatively small portion of the knife blade which becomes dull after extremely short periods of use so that the apparatus must be arrested at frequent intervals in order to allow for a replacement of the knife. Alternately, the apparatus must be provided with a complex mechanism for displacing the knife relative to its holder so as to move different portions of the blade into severing engagement with the tube.
Cutoffs of the type normally employed for subdividing a continuous rod of tobacco into discrete cigar bunches are very expensive and, therefore, there exists an urgent need for relatively simple but reliable means for separating a succession of interconnected wrapped cigar bunches from each other to form discrete cigars.
In accordance with still another proposal, the apparatus employs a first conveyor which rotates successive bunches of a single file about their axes and moves the bunches lengthwise while a device feeds an adhesive-coated web obliquely into the path of successive bunches so that the web is convoluted around the bunches and forms a continuous tube consisting of partially overlapping helices. The tube is then engaged by a second conveyor which rotates the tube at a higher speed so that portions of the tube between successive bunches are twisted and thereby automatically separated from each other. Such proposal has met with limited success because the separation of wrapped bunches is not reproducible with a sufficient degree of accuracy and also because the twisted portions of the tube affect the appearance of the cigars.